Cambridge Assessment International Education Cambridge International Advanced Subsidiary and Advanced Level BIOLOGY 9700/1 Paper Advanced Practical Skills 1 MARK SCHEME Maximum Mark: 40 Published This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge International will not enter into discussions about these mark schemes. Cambridge International is publishing the mark schemes for the series for most Cambridge IGCSE, Cambridge International A and AS Level components and some Cambridge O Level components. IGCSE is a registered trademark. This document consists of 6 printed pages. UCLES [Turn over
Mark scheme abbreviations ; separates marking points / alternative answers for the same point R reject A accept (for answers correctly cued by the question, or by extra guidance) AW alternative wording (where responses vary more than usual) underline actual word given must be used by candidate (grammatical variants accepted) max indicates the maximum number of marks that can be given ora or reverse argument mp marking point (with relevant number) ecf error carried forward I ignore UCLES Page 2 of 6
1(a)(i) lose + less ; 1 1(a)(ii) completes Fig. 1. drawing all three directions correctly (up + level + down) ; 1 1(b)(i) for at least 4 suitable concentrations of S ; e.g. 0.8, 0.6, 0.4 and 0.2 decides correct volume of sucrose volumes for selected concentrations ; decides correct total volumes (40 cm ) for each concentration ; 1(b)(ii) decides appropriate length of potato pieces ; e.g. 4.0 cm 1(b)(iii) 1 table drawn + heading, concentration of sucrose solution / mol dm ; 1 6 2 heading, direction of movement ; records speed of movement in an appropriate way ; 4 decides to do repeated drops ; 5 results for at least 4 concentrations of sucrose ; 6 correct sequence of directions ; UCLES Page of 6
1(b)(iv) correct estimate of concentration of sucrose according to results in (b)(iii) ; 1 1(b)(v) identifies one significant source of error ; e.g. difficulty of measuring and cutting pieces of potato to correct dimensions 1(b)(vi) uses increased number of concentrations of sucrose solution ; 1 between 2 stated concentrations appropriate to candidate s results ; read off from graph of results or replicate ; 1(b)(vii) no net movement of water or reference to dynamic equilibrium ; 1 1(b)(viii) shows on graph reading at 0. mol dm to estimate the water potential ; 2 correct estimate for water potential + kpa 10 2 ; UCLES Page 4 of 6
2(a)(i) 1 quality of line (thin and continuous) for at least 6 grains drawn ; 5 2 draws only starch grains from F + only starch grains from G ; grains not overlapping ; 4 starch grains from F drawn as oval shapes + starch grains from G drawn as angular shapes ; 5 uses one label line + one label, X, to identify surface markings on grains ; 2(a)(ii) correct annotations describing observable differences between the starch grains from F and G ;;; e.g. size of grains from F larger than grains from G 2(b)(i) 1 (x-axis) time / minutes + (y-axis) reducing sugar concentration / µm ; 4 2 (scale on x-axis) 10.0 to 2 cm, labelled at least each 2 cm + (scale on y-axis) 2.0 to 2 cm, labelled at least each 2 cm ; correct plotting of six points with a small cross or dot in circle ; 4 six plots, joined plot to plot + thin line drawn ; 2(b)(ii) 1 states correct reducing sugar concentration at 5 minutes (x) and 15 minutes (y) ; 2 shows x minus y ; shows answer to mp2 divided by y and multiplied by 100 ; UCLES Page 5 of 6
2(c) 1 plan diagram of appropriate size + no cells + no shading ; 5 2 correct section drawn + draws only vascular bundles ; draws epidermis as 2 lines ; 4 draws at least one vascular bundle divided into at least sections ; 5 uses one label line + one label to identify phloem ; UCLES Page 6 of 6